Field of the Invention
The present invention relates to an image forming apparatus that operates in one of a plurality of power modes, a method for controlling the image forming apparatus, and a storage medium.
Description of the Related Art
In recent years, with an increasing concern over the environment, many devices having environmentally friendly functions have been commercialized. Such functions include, for example, an energy saving mode (hereinafter referred to as “power saving mode”). An image forming apparatus has a power saving mode as well. The image forming apparatus is controlled to continue the power saving mode as long as possible while the image forming apparatus is not in use, depending on the usage status and wait time of the user of the image forming apparatus.
However, as the image forming apparatus has become multifunctional, the usage patterns of users and the contents of function settings have become various. As a result, an increasing number of standby modes are provided in the power saving mode, leading to variations in the power consumption in the power saving mode. Accordingly, the number of factors for returning the image forming apparatus from the power saving mode has also increased. In other words, the ways of shifting to and returning from the power saving mode have become complicated and difficult to control.
For example, a Universal Serial Bus (USB) controller can be connected or disconnected at an arbitrary timing by a user's personal computer (PC) serving as a USB host device. It is also known that on the image forming apparatus side, the standby mode of the power saving mode is changed depending on the connection or disconnection of the USB host device.
Japanese Patent Application Laid-Open No. 2004-227064 discusses a technique for controlling the operations in an apparatus by recognizing the connection or disconnection of a USB host device based on a VBUS signal of a USB. In Japanese Patent Application Laid-Open No. 2004-227064, VBUS connection or disconnection is associated with the operation of a component in the apparatus. For example, when the VBUS connection is detected, a print job may be received from a PC, and therefore the VBUS connection is associated with turning ON of a printer. Similarly, the VBUS disconnection is associated with turning OFF of the printer to maintain low power consumption.
Such a configuration can realize responsiveness at the time of the VBUS connection, and power saving at the time of the VBUS disconnection. However, this configuration may not be able to meet the needs of all users. For example, in an environment where a job can be received via a network even if the VBUS is disconnected, there may be many users who desire to maintain the responsiveness while keeping the printer turned ON even after the VBUS is disconnected.